html5 canvas实现图片玻璃碎片特效

今天要为大家带来一款html5 canvas实现的图片玻璃碎片特效。图片以玻璃碎片的形式出现到界面中，然后似玻璃被打碎的效果渐消息。效果图如下：

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实现代码：

html代码：

  <img src="city_copy.jpg" id="src_img" class="hidden">
    <div id="container" style="-webkit-perspective: 500px;">
        <div>

            <script src="delaunay.js"></script>
            <script src="TweenMax.min.js"></script>

js代码：

               // canvas settings
                var imageWidth = 768,
    imageHeight = 485;

                var vertices = [],
    indices,
    boxes = [];

                var image,
    fragments = [],
    container = document.getElementById('container');

                window.onload = function () {
                    image = document.getElementById('src_img');

                    triangulate();
                    makeBoxes();
                    makeFragments();
                };

                function triangulate() {
                    var x,
        y,
        dx = imageWidth / 8,
        dy = imageHeight / 8,
        offset = 0.5;

                    for (var i = 0; i <= imageWidth; i += dx) {
                        for (var j = 0; j <= imageHeight; j += dy) {
                            if (i && (i !== imageWidth)) x = i + randomRange(-dx * offset, dx * offset);
                            else x = i;

                            if (j && (j !== imageHeight)) y = j + randomRange(-dy * offset, dy * offset);
                            else y = j;

                            vertices.push([x, y]);
                        }
                    }

                    indices = Delaunay.triangulate(vertices);
                }

                function makeBoxes() {
                    var p0, p1, p2,
        xMin, xMax,
        yMin, yMax;

                    for (var i = 0; i < indices.length; i += 3) {
                        p0 = vertices[indices[i + 0]];
                        p1 = vertices[indices[i + 1]];
                        p2 = vertices[indices[i + 2]];

                        xMin = Math.min(p0[0], p1[0], p2[0]);
                        xMax = Math.max(p0[0], p1[0], p2[0]);
                        yMin = Math.min(p0[1], p1[1], p2[1]);
                        yMax = Math.max(p0[1], p1[1], p2[1]);

                        boxes.push({
                            x: xMin,
                            y: yMin,
                            w: xMax - xMin,
                            h: yMax - yMin
                        });
                    }
                }

                function makeFragments() {
                    var p0, p1, p2,
        box,
        fragment;

                    TweenMax.set(container, { perspective: 500 });

                    var tl0 = new TimelineMax({ repeat: -1 });

                    for (var i = 0; i < indices.length; i += 3) {
                        p0 = vertices[indices[i + 0]];
                        p1 = vertices[indices[i + 1]];
                        p2 = vertices[indices[i + 2]];
                        box = boxes[i / 3];

                        fragment = new Fragment(p0, p1, p2, box);

                        var rx = randomRange(30, 60) * ((i % 2) ? 1 : -1);
                        var ry = randomRange(30, 60) * ((i % 2) ? -1 : 1);
                        var tl1 = new TimelineMax();

                        TweenMax.set(fragment.canvas, {
                            y: box.y - 1000
                        });

                        tl1.to(fragment.canvas, randomRange(0.9, 1.1), {
                            y: box.y,
                            ease: Back.easeOut
                        });
                        tl1.to(fragment.canvas, 0.5, {
                            z: -100,
                            ease: Cubic.easeIn,
                            delay: 0.4
                        });
                        tl1.to(fragment.canvas, randomRange(1, 1.2), {
                            rotationX: rx,
                            rotationY: ry,
                            z: 250,
                            alpha: 0,
                            ease: Cubic.easeOut
                        });

                        tl0.insert(tl1);

                        fragments.push(fragment);
                        container.appendChild(fragment.canvas);
                    }
                }

                function randomRange(min, max) {
                    return min + (max - min) * Math.random();
                }

                Fragment = function (v0, v1, v2, box) {
                    this.v0 = v0;
                    this.v1 = v1;
                    this.v2 = v2;
                    this.box = box;

                    this.canvas = document.createElement('canvas');
                    this.canvas.width = this.box.w;
                    this.canvas.height = this.box.h;
                    this.canvas.style.width = this.box.w + 'px';
                    this.canvas.style.height = this.box.h + 'px';
                    this.ctx = this.canvas.getContext('2d');

                    TweenMax.set(this.canvas, {
                        x: this.box.x,
                        y: this.box.y
                    });

                    this.ctx.translate(-this.box.x, -this.box.y);
                    this.ctx.beginPath();
                    this.ctx.moveTo(this.v0[0], this.v0[1]);
                    this.ctx.lineTo(this.v1[0], this.v1[1]);
                    this.ctx.lineTo(this.v2[0], this.v2[1]);
                    this.ctx.closePath();
                    this.ctx.clip();
                    this.ctx.drawImage(image, 0, 0);
                }; //@ sourceURL=pen.js

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